US9488056B2 - Propeller blade with modified spar layup - Google Patents

Propeller blade with modified spar layup Download PDF

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Publication number
US9488056B2
US9488056B2 US13/873,705 US201313873705A US9488056B2 US 9488056 B2 US9488056 B2 US 9488056B2 US 201313873705 A US201313873705 A US 201313873705A US 9488056 B2 US9488056 B2 US 9488056B2
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Prior art keywords
propeller blade
layers
layer
mid
foam core
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US13/873,705
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US20130287584A1 (en
Inventor
David P. Nagle
Patrice Brion
Ludovic Prunet
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Ratier Figeac SAS
Hamilton Sundstrand Corp
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Ratier Figeac SAS
Hamilton Sundstrand Corp
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Assigned to HAMILTON SUNDSTRAND CORPORATION reassignment HAMILTON SUNDSTRAND CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NAGLE, DAVID P.
Assigned to RATIER-FIGEAC SAS reassignment RATIER-FIGEAC SAS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: Brion, Patrice, PRUNET, LUDOVIE
Assigned to RATIER-FIGEAC SAS reassignment RATIER-FIGEAC SAS CORRECTIVE ASSIGNMENT TO CORRECT THE SPELLING OF THE SECOND ASSIGNOR'S NAME LUDOVIE PRUNET PREVIOUSLY RECORDED ON REEL 031995 FRAME 0246. ASSIGNOR(S) HEREBY CONFIRMS THE CORRECT SPELLING IS LUDOVIC PRUNET. Assignors: Brion, Patrice, Prunet, Ludovic
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/147—Construction, i.e. structural features, e.g. of weight-saving hollow blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B64C11/20—Constructional features
    • B64C11/26—Fabricated blades
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49316—Impeller making
    • Y10T29/49332—Propeller making

Definitions

  • the present invention relates to propellers and, in particular, to propeller blades formed having a foam spar core.
  • Modern propeller blades typically include root portions which extend into the hub arm of the hub of the propeller system and which are secured to and rotatable relative to the hub arm via a retention assembly.
  • the retention assembly includes one or a plurality of ball bearing assemblies which permit the rotation of the blade in the hub arm for accomplishing pitch change of the blade for altering the speed of the propeller and accordingly, the aircraft.
  • the blades are typically formed by surrounding a foam spar core with a resin impregnated fabric that is braided on to the form spar core. Leading and trailing edges of the blade are then formed over the fabric and surrounded by, for example, a Kevlar sock. Such blades are light and effective for their intended purposes.
  • a propeller blade that includes a foam core and a structural layer formed of multiple layers that surrounds at least a portion of the foam core, is disclosed.
  • the structural layer includes a mid-thickness location defined between the foam core and an outer edge of the structural layer and the multiple layers include at least one unidirectional layer and at least one biased layer disposed asymmetrically about the mid-thickness location.
  • a method of forming a propeller blade includes forming a foam core; and disposing a plurality of braided layers over at least a portion of the foam core to form a structural layer having mid-thickness location defined between the foam core and an outer edge of the structural layer, the plurality of layers includes unidirectional layers and a biased layers disposed asymmetrically about the mid-thickness location.
  • FIG. 1 is a plan-view of a prior art propeller blade
  • FIG. 2 is a cross-section of the propeller blade shown in FIG. 1 ;
  • FIG. 3 is a plan view of a spar having a first ply of structural layer formed thereon;
  • FIG. 4 is a plan view of a spar having a second ply of structural layer formed thereon.
  • FIG. 5 is a conceptual view showing a spar layup and used to describe the difference between balanced and unbalanced spar layups.
  • FIG. 6 shows an asymmetrical spar layup
  • FIG. 1 a plan view of a conventional propeller blade 100 is illustrated and will be used to define certain terms, explain how a propeller blade is generally made, and to illustrate the differences between embodiments of the present invention and the prior art.
  • FIG. 2 is a cross-section of the propeller blade 100 of FIG. 1 taken along line A-A, for these purposes.
  • the blade 100 is formed by first forming a spar 102 .
  • the spar 102 includes a spar foam core 104 surrounded by a structural layer 106 .
  • the core 104 is typically formed of a foam material that is injected into a mold.
  • the mold can include a layer of fiberglass on the walls thereof that to which the foam of the core 104 adheres. As such, the core 104 can be surrounded by a layer of fiberglass (not shown).
  • the structural layer 106 is typically formed of a dry braided carbon fiber which is subsequently resin injected, or a resin-impregnated fabric material (e.g. resin impregnated carbon fabric) and disposed such that it surrounds the core 104 (and the fiberglass layer if it is included).
  • the structural layer 106 is typically braided onto the core 104 .
  • the spar 102 is heated to set the resin in the structural layer 106 .
  • Considerable thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106 .
  • CTE coefficients of thermal expansion
  • the spar 102 is formed such that a portion of it is surrounded by a root portion 108 that allows the blade 100 to be connected to a hub (not shown). Rotation of the hub causes the blade 100 to rotate and, consequently, causes the generation of thrust to propel an aircraft. In the following discussion, it shall be assumed that the blade 100 rotates in the clockwise direction.
  • the root portion 108 is sometimes referred to as a “tulip” in the industry and is typically formed of a metal.
  • leading edge foam 110 and trailing edge foam 112 are formed on the leading and trailing edges 114 , 116 , respectively of the spar 102 .
  • the leading edge foam 110 , trailing edge foam 112 and the spar 102 can then be encased in an outer layer 118 .
  • the outer layer 118 can be formed of Kevlar and be in the form of a sock that is pulled over the assembly that includes the leading edge foam 110 , trailing edge foam 112 and the spar 102 .
  • the outer layer 118 could be formed in other manners as well.
  • thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106 .
  • thermal stresses can be created between the core 104 and the structural layer 106 due to the wide range of temperatures experienced by the propeller blade 100 in normal operation.
  • FIG. 3 is a plan view of a spar 204 after a first braid ply 206 a of a structural layer has been applied over the spar foam core 205 .
  • the first braid ply 206 a is formed as a biased braid in this embodiment.
  • the first blade ply 206 a is formed of several structural fibers 210 that cross one another at a braid angle ⁇ .
  • the structural fibers 210 are formed of carbon or a carbon based material. While not illustrated, it shall be understood that the structural layer could include other fibers between the structural fibers 210 formed of, for example, fiberglass or another suitable material. The other fibers do not provide appreciable (as compared to the structural fibers 210 ) stiffness to the spar 204 .
  • the braid angle ⁇ is about 90 degrees. Of course, this angle could be varied depending on the context.
  • the manner of forming the biased braid ply 206 a is known in the art and not discussed further herein.
  • FIG. 4 is a plan view of spar 204 after a second braid ply 206 b of a structural layer has been applied to the foam spar core 205 .
  • the second braid ply 206 b is formed on top the first braid ply 206 a (not shown for clarity) in one embodiment.
  • the second braid ply 206 b is a unidirectional ply that includes carbon fibers 210 that generally extend along the spar 204 in the span wise direction X.
  • the structural fibers 210 of the second braid ply 206 b are generally parallel to one another.
  • the first braid ply 206 a also includes other fibers 212 between the structural fibers 210 formed of, for example, fiberglass or another suitable material. The other fibers do not provide appreciable (as compared to the structural fibers 210 ) stiffness to the spar core.
  • plies 504 , 508 , 506 , and 510 are arranged about a mid-thickness location 500 of the spar layup 501 .
  • plies 504 and 510 are formed of the same material, thickness, and fiber orientation.
  • plies 506 and 508 are formed of the same material, thickness, and fiber orientation.
  • the spar layup 501 (e.g., order of types of plies) is modified from the prior art such that the spar is unbalanced. Such a modification may improve the thermal behavior of the spar 204 . For instance, such a configuration could result in spar and camber sides providing some degree of compression to the spar foam core 205 after the resin injection cool down to room temperature, thereby improving the bond strength between the foam spar core 205 and the structural layer 206 .
  • the spar layup 501 is formed such that layers on opposing sides of the mid-thickness location 500 are not symmetrical.
  • mid-thickness location 500 there could be more layers of biased braids on one side of the mid-thickness location 500 than the other (as shown in FIG. 6 ).
  • the exact ordering can be varied so long and the layers are not symmetrical (e.g., asymmetrical) about the mid-thickness location 500 of the spar layup 501 .
  • mid-thickness location 500 is defined between the foam core 502 and an outer edge 512 of the spar layup 501 (e.g., in the middle of the structural layer).
  • one or more additional unidirectional plies may be provided having structural fibers that extend in the chord wise direction Y to stiffen the spar 204 in the chordwise direction. This will reduce the outward deflection of the spar as the blade bends due to operating loads, resulting in lower thru-thickness tensile stresses in the foam, thereby preventing or reducing spar foam cracks.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Architecture (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Moulding By Coating Moulds (AREA)
  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)
  • Laminated Bodies (AREA)
US13/873,705 2012-04-30 2013-04-30 Propeller blade with modified spar layup Active 2035-05-08 US9488056B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP12305486.8 2012-04-30
EP12305486.8A EP2660146B1 (de) 2012-04-30 2012-04-30 Propellerblatt mit modifizierter Holmlaminierung
EP12305486 2012-04-30

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US20130287584A1 US20130287584A1 (en) 2013-10-31
US9488056B2 true US9488056B2 (en) 2016-11-08

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EP (1) EP2660146B1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160076552A1 (en) * 2014-09-16 2016-03-17 General Electric Company Composite airfoil structures
EP3556544A1 (de) 2018-04-17 2019-10-23 Ratier-Figeac SAS Propellerblattholm
US20230081843A1 (en) * 2020-02-18 2023-03-16 Safran Aircraft Engines Composite blade for a turbine engine rotor
US20230313687A1 (en) * 2022-04-04 2023-10-05 General Electric Company Airfoil assembly with a structurally reinforced foam core
US12018586B2 (en) 2022-09-06 2024-06-25 General Electric Company Airfoil assembly with tensioned blade segments
US12030616B2 (en) * 2020-02-18 2024-07-09 Safran Aircraft Engines Composite blade for a turbine engine rotor

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9139287B2 (en) * 2012-06-26 2015-09-22 Hamilton Sundstrand Corporation Propeller blade with carbon foam spar core
WO2016025386A1 (en) 2014-08-15 2016-02-18 Sikorsky Aircraft Corporation Rotor blade spar formation with automated fiber placement
US10434687B2 (en) 2014-12-17 2019-10-08 Sikorsky Aircraft Corporation Composite laminate tooling and method of forming a composite part using the tooling

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3782856A (en) 1972-05-31 1974-01-01 United Aircraft Corp Composite aerodynamic blade with twin-beam spar
EP0256916A1 (de) 1986-07-28 1988-02-24 AEROSPATIALE Société Nationale Industrielle FVK-Blatt mit doppeltem Holm und Torsionskasten und mit Sandwich-Waben-Schichtbeplankung und sein Herstellungsverfahren
US4810167A (en) 1986-12-08 1989-03-07 Hartzell Propeller Inc. Composite aircraft propeller blade
US5127802A (en) 1990-12-24 1992-07-07 United Technologies Corporation Reinforced full-spar composite rotor blade
US5222297A (en) 1991-10-18 1993-06-29 United Technologies Corporation Composite blade manufacture
US5269658A (en) * 1990-12-24 1993-12-14 United Technologies Corporation Composite blade with partial length spar
US5939007A (en) 1994-08-31 1999-08-17 Sikorsky Aircraft Corporation Method for manufacture of a fiber reinforced composite spar for rotary wing aircraft

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3782856A (en) 1972-05-31 1974-01-01 United Aircraft Corp Composite aerodynamic blade with twin-beam spar
EP0256916A1 (de) 1986-07-28 1988-02-24 AEROSPATIALE Société Nationale Industrielle FVK-Blatt mit doppeltem Holm und Torsionskasten und mit Sandwich-Waben-Schichtbeplankung und sein Herstellungsverfahren
US4810167A (en) 1986-12-08 1989-03-07 Hartzell Propeller Inc. Composite aircraft propeller blade
US5127802A (en) 1990-12-24 1992-07-07 United Technologies Corporation Reinforced full-spar composite rotor blade
US5269658A (en) * 1990-12-24 1993-12-14 United Technologies Corporation Composite blade with partial length spar
US5222297A (en) 1991-10-18 1993-06-29 United Technologies Corporation Composite blade manufacture
US5939007A (en) 1994-08-31 1999-08-17 Sikorsky Aircraft Corporation Method for manufacture of a fiber reinforced composite spar for rotary wing aircraft

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
European Search Report, EP12305486.8,, Oct. 15, 2012, 8 pages.

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160076552A1 (en) * 2014-09-16 2016-03-17 General Electric Company Composite airfoil structures
US10099434B2 (en) * 2014-09-16 2018-10-16 General Electric Company Composite airfoil structures
EP3556544A1 (de) 2018-04-17 2019-10-23 Ratier-Figeac SAS Propellerblattholm
US11401030B2 (en) 2018-04-17 2022-08-02 Ratier-Figeac Sas Propeller blade spar
US20230081843A1 (en) * 2020-02-18 2023-03-16 Safran Aircraft Engines Composite blade for a turbine engine rotor
US12030616B2 (en) * 2020-02-18 2024-07-09 Safran Aircraft Engines Composite blade for a turbine engine rotor
US20230313687A1 (en) * 2022-04-04 2023-10-05 General Electric Company Airfoil assembly with a structurally reinforced foam core
US11795827B1 (en) * 2022-04-04 2023-10-24 General Electric Company Airfoil assembly with a structurally reinforced foam core
US12018586B2 (en) 2022-09-06 2024-06-25 General Electric Company Airfoil assembly with tensioned blade segments

Also Published As

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EP2660146A1 (de) 2013-11-06
EP2660146B1 (de) 2018-01-31
US20130287584A1 (en) 2013-10-31

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